Pidgin has an interessting bug : it cannot connect to MSN server since late last night. The bug report for Fedora is here : https://bugzilla.redhat.com/show_bug.cgi?id=479627 and the Pidgin one is here : http://www.nabble.com/-8080%3A-Unable-to-retrieve-MSN-address-book-td21407542.html
I know, we should not use MSN, but sometimes we have to!
In the moment, you can compile the msn-pecan plugin to change from the MSN protocol to WLM protocol. It’s not the recommended solution but if you really need MSN connectivity, it should work.